Design and Analysis of a Novel Continuous Ejector Pin Mechanism for Mini-LED Mass Transfer

The continuous mechanical Mini-LED chip mass transfer approach is greatly attractive for the rapidly growing Mini-LED display applications. Compared with the traditional intermittent eject pin transfer method, the continuous method significantly decreases the transfer duration, thus the production efficiency is greatly improved. To this end, a novel continuous ejector pin mechanism with 2-degree of freedom (DOF) and sub-centimeter-scale stroke is designed for continuous mechanical Mini-LED chip mass transfer, which is driven by the piezoelectric actuators and generates the displacement via the compliant mechanism. Specifically, the Continuous Ejector Pin Mechanism (CEPM) provides the decoupled displacements along horizontal and vertical directions such that the ejector pin can keep relatively stationary with the moving chip carrier and achieves chip transfer from the blue film to the substrate. The mechanism consists of a double-bridge cascade structure in the vertical direction, and a bridge-DPFR (double parallel four-reed flexible module) parallel structure in the horizontal direction which is capable of achieving large stroke, high frequency, and high precision motion of the pinning system. Kinetostatic analysis of the mechanism is carried out by using the matrix representation base on Von-Mises beam theory and small deformation assumption. Finally, the performance of the installations is analyzed and evaluated by the finite element analysis (FEA) method.